Such release ski bindings are described in German Pat. No. 2 533 337. In these conventional ski bindings the spring of the holding mechanism acts through a piston onto an approximately mushroom-shaped follower member, which is supported pivotally to all sides in the housing of the holding mechanism. The stem portion of the mushroom-shaped follower member is received in a recess of a ski-fixed fitting. In these known ski bindings, the ski shoe is held at its tip or toe by means of a rigid bar on the sole plate. In the case of a fall of the skier to the rear, the ski shoe is therefore released only with great difficulty.
This disadvantage is avoided in the ski binding according to German Pat. No. 2 324 078, however, this binding is complicated in its design. That is, the release mechanism is housed in the space between the base plate and the sole plate. This, however, requires special seal structure to prevent the penetration of snow and dirt therein. Furthermore, the installation is complicated and expensive.
The goal of the invention is to overcome the disadvantages of the conventional designs and to provide a release ski binding of the above-mentioned type, which is simple in its design and in which the ski shoe is reliably held during skiing, however, is immediately released in the case of a fall.
This goal is inventively attained primarily by providing a locking mechanism having two clamping jaws which engage laterally the ski shoe and which are constructed as two-arm levers, which clamping jaws are pivotal on the sole plate about axes which extend in the longitudinal direction of the ski and by the transverse axis of the heel holder being movable in the longitudinal direction of the ski and being under the influence of a pressure spring which urges it toward the tip of the ski.
The concept supporting one-arm clamping jaws, which laterally engage the ski shoe, on a sole plate and to move them through a slide plate with the help of wedge-shaped shoulders into the clamping position is actually already known through the teachings in German OS Nos. 2 943 209 and 3 026 918. However, in these constructions the locking spring acts directly onto the clamping jaws, the load of which is utilized for the automatic release of the ski binding, and which brings about certain inexactnesses compared with the ski bindings of the above-mentioned type in which the angle of traverse of the sole plate is decisive for effecting the opening of the locking mechanism.
Of course, various solutions exist to swing the clamping jaws into the clamping position. However, it has been proven to be particularly preferable if the two clamping jaws are movable into the clamping position by means of clamping wedges movably supported on the sole plate and are under the influence of springs, in particular a pressure or compression spring. In this manner, it is possible to bring about with relatively small spring forces a strong urging of the upper arms of the clamping jaws on the ski shoe.
Furthermore, the invention provides that the two clamping wedges are hingedly connected by a crossbar to a pull rod which extends in a direction toward the tail end of the ski, which pull rod is loaded by the pressure spring in a direction toward the tip end of the ski. This measure contributes to the release of the two wedges occurring evenly.
Furthermore, according to a different characteristic of the invention, the crossbar is connected through a pin, received in a slotted hole in the pull rod, to said pull rod. It is made possible through this measure that the pull rod, which not only handles the opening of the two clamping jaws, but also, as will be discussed below, unlocks the heel holder, carries out these two operations in specified timely intervals one after the other.
According to a further development of the invention, the transverse axis for the heel holder is supported on a piston guided in a hole in the sole plate extending in the longitudinal direction of the sole plate, and a second piston is also movably supported in said hole, which second piston is connected through a transverse bolt to the fork-shaped constructed end of the pull rod. The pressure spring is arranged between both pistons. Furthermore, the second piston has a piston rod secured thereto and which projects from the hole into operative engagement with an operating member of the holding mechanism. The pressure spring is, through this development, not only utilized for urging the heel holder onto the ski shoe during skiing, but at the same time for releasing the two clamping jaws, for example in the case of a fall.
In order to hold the heel holder reliably in the skiing position, various locking mechanisms can be used. However, it has been proven as being particularly preferable to provide at least one hook-shaped locking member hingedly connected to the heel holder, which locking member is under the influence of a torsion spring and in the skiing position of the ski binding grips with its hook under a projection of the sole plate. It is thereby preferable if a stop on the pull rod is associated with the locking member. The stop permits a release of the heel holder prior to the two clamping jaws having opened, so that first the heel and then the toe-piece of the ski shoe is released.
According to a further characteristic of the invention, the heel holder is under the influence of a helical erecting spring supported at one end on a transverse axis supported on the sole plate and at the other end on a transverse axis on the heel holder. This type of support for the erecting spring permits the heel holder to always be under the pressure of the erecting spring, regardless of whether the heel holder is in the position (stepping-in position) which is caused by the pressure spring and which is moved forwardly toward the tip of the ski or in the moved-back position (skiing position) which is caused by a stepping down by the ski shoe.
Finally, the invention provides that the heel holder is guided in a vertical guide slot in the housing on the sole plate. This causes the axis for the heel holder to be substantially protected, since independent from whether the ski shoe is inserted into the ski binding parallel with respect to the vertical longitudinal center plane of the ski or inclined with respect to same, a force is applied onto the axis, which force is always only normal with respect to the axis. Furthermore, a bending of the heel holder during a rough stress or loading of the ski binding is also resisted.